But Kassovitz has his principles. "Titles are important: they're the first contact a viewer has with a film. When you go into a cinema to see a film called Hate, you don't watch it in the same way as a film called Les Visiteurs," he says, referring to the time-travel comedy that stormed French cinemas two years ago. "There are some things I don't feel like doing, even though they would put more bums on seats: appearing on the cover of [the right-wing] Figaro magazine, for example. I'm trying to maintain a little control over the way the film is sold."
Kassovitz was speaking last May, at the Cannes Film Festival, just before Hate opened in Paris. And it seems his instincts were right: it went on to become a French box-office hit - and media event - of the summer. Newspapers battened eagerly on the film's theme, launching a spree of editorialising about police brutality and the government's shameful neglect of public housing - or else, at the opposite end of the political spectrum, bemoaning the breakdown of law and order in working-class kids. The Prime Minister, Alain Juppe, responded by commissioning a special screening of the film for the cabinet, which ministers were required to attend. All of a sudden, the government was keen to see what it was up against.
Kassovitz fuelled the flames by declaring that Hate was "against the cops" - who riposted, rather mildly in the circumstances, that if the official misconduct shown in the film was unacceptable, so was the crime that the police were fighting. "Having said that," added a spokesman, "this film is a beautiful work of cinematographic art that can make us more aware of certain realities." (Rather difficult to imagine British police reacting to a comparable attack by one of our film-makers with the same cinephilia.)
The seeds of Hate were sown two years ago with a notorious real-life case: a black youth, Makome, was shot in the head while in police custody. Kassovitz was there on the protest marches, which rapidly turned into riots. Then he set to thinking of the youngster who woke up one morning never imagining that this day would be his last.
His film follows 24 hours in the lives of its three protagonists; the inter-titles, clocking the passing of time, also convey the sense of a countdown to some sort of explosion. But Hate is none the less more even- handed than it first appears, filtering events through the eyes of the most level-headed member of the trio, a would-be boxer hoping that sporting success will spring him from the ghetto.
All the same, seven or eight local councils refused to allow the film crew on to their territory; in these cases the film's title was a most definite turn-off, and the permits were secured by temporarily renaming the script the blander Droit de Cite and divesting it of its violent final scene.
Hate was just one of a mini-wave of French movies all set on housing estates (others include Rai, Krim and L'Etat des Lieux) and all opening in Paris within the space of a few weeks. But several qualities set Kassovitz's film apart from its lower-budget brothers: the bold and confident visual elan - which secured the film a place in competition at Cannes and earned it the prize for Best Direction - and also its ability to confront its audience with some hard truths while showing them a good time.
At our interview Kassovitz sported a baseball cap with the peak turned forward, which, he says, means he's serious, and not a radical chic poseur. He is unapologetic about the fact that he has never lived on a council estate. His parents were film-makers: the director Peter Kassovitz and the film editor Chantal Remy. And both were political activists: Kassovitz pere fought in the underground resistance in Nicaragua. From them, their son learnt a love of cinema and a hatred of injustice.
But he was also wearing a Jurassic Park T-shirt, which, he says, means hooray for Hollywood. "Just because I don't make films like that doesn't mean I don't enjoy them," he says, citing as influences the Marx Brothers, Monty Python and kung fu movies. "I like films that entertain you first and foremost - if afterwards you find you've learnt something, it's a bonus."
Actually, Spike Lee is the comparison that first springs to mind. Hate traces the tragic and inevitable consequences when, in the course of a riot, a police gun falls into the wrong hands, and has been compared to Do the Right Thing, which also unfolds in the course of a single day.
Kassovitz's first film, a sweet comedy called Metisse (the movie was released briefly under the English titles Blended and Cafe au Lait), centred on a beautiful and independent mulatto woman who is pregnant but unsure which of her two lovers - one black, one white - is the father. It was "Two Men and a Baby" with bite, Kassovitz always undercutting the story's stickier, more sentimental moments. The film was promising and highly enjoyable, although Hate represents a leap forward in both style and substance.
The obvious echoes there were of Lee's debut, She's Gotta Have It: like Lee in his own film, Kassovitz played one of the suitors, a bespectacled, bike-riding geek. He also appears briefly in Hate, as a fascist skinhead - mainly, he says, because he thought he might have problems persuading another actor to take a role in which he gets punched in the face and then shot and is seen only from the back.
The new film's other sweetener is its robust comic vision and salty dialogue, much of it in verlan (street slang), a subtitler's nightmare. Most of the humour is strictly of the gallows kind. "Just because you're laughing doesn't mean it's funny. People who have the greatest sense of fun are often those who haven't led a good life. The best Jewish jokes are very tough," says Kassovitz, whose grandmother is a death-camp survivor.
In the scene that most sharply illustrates this approach, the three youths are buttonholed by a Holocaust survivor; he tells them a scatological, tragi-comic story about a prisoner caught out by the call of nature, of which the punchline and motto is that the kids, deprived as they are, have no cause for complaint while they can still empty their bowels in comparative peace.
Consequent to Hate's success in France (it has yet to open in the US and most foreign markets), its director, who turned 28 in August, finds himself swiftly crowned the latest wonderboy of the new French cinema. Such acclaim has turned many lesser heads, but Kassovitz seems a fairly sensible sort (encouragingly, we read that he has declined a bid by the supermarket chain Monoprix to launch a line of street-cred Hate leisurewear). Whatever happens, one hopes he'll continue to wear his baseball cap the right way round.
n 'Hate' plays in the London Film Festival on 3 Nov. It opens in London on 17 Nov